/*
    * Copyright 2015 Data Archiving and Networked Services (an institute of
    * Koninklijke Nederlandse Akademie van Wetenschappen), King's College London,
    * Georg-August-Universitaet Goettingen Stiftung Oeffentlichen Rechts
    *
    * Licensed under the EUPL, Version 1.1 or – as soon they will be approved by
    * the European Commission - subsequent versions of the EUPL (the "Licence");
    * You may not use this work except in compliance with the Licence.
    * You may obtain a copy of the Licence at:
   *
   * https://joinup.ec.europa.eu/software/page/eupl
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the Licence is distributed on an "AS IS" basis,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the Licence for the specific language governing
   * permissions and limitations under the Licence.
   */
  
  package eu.ehri.extension;
  
  import com.fasterxml.jackson.core.type.TypeReference;
  import com.google.common.collect.Iterables;
  import com.google.common.collect.Maps;
  import com.tinkerpop.blueprints.CloseableIterable;
  import com.tinkerpop.blueprints.Graph;
  import com.tinkerpop.blueprints.Vertex;
  import com.tinkerpop.blueprints.util.io.graphson.GraphSONMode;
  import com.tinkerpop.blueprints.util.io.graphson.GraphSONWriter;
  import eu.ehri.extension.base.AbstractResource;
  import eu.ehri.project.acl.PermissionType;
  import eu.ehri.project.acl.wrapper.AclGraph;
  import eu.ehri.project.core.Tx;
  import eu.ehri.project.definitions.Ontology;
  import eu.ehri.project.models.EntityClass;
  import eu.ehri.project.models.Group;
  import eu.ehri.project.models.UserProfile;
  import eu.ehri.project.models.base.Accessor;
  import eu.ehri.project.persistence.Bundle;
  import eu.ehri.project.tools.JsonDataExporter;
  import org.neo4j.graphdb.GraphDatabaseService;
  
  import javax.ws.rs.Consumes;
  import javax.ws.rs.GET;
  import javax.ws.rs.POST;
  import javax.ws.rs.Path;
  import javax.ws.rs.Produces;
  import javax.ws.rs.QueryParam;
  import javax.ws.rs.core.Context;
  import javax.ws.rs.core.MediaType;
  import javax.ws.rs.core.Response;
  import javax.ws.rs.core.StreamingOutput;
  import java.io.IOException;
  import java.util.HashMap;
  import java.util.List;
  import java.util.Map;
  
  /**
   * Provides additional Admin methods needed by client systems
   * and general graph-maintenance functionality.
   */
  @Path(AdminResource.ENDPOINT)
  public class AdminResource extends AbstractResource {
  
      public static final String ENDPOINT = "admin";
      public static final String DEFAULT_USER_ID_PREFIX = "user";
      public static final String DEFAULT_USER_ID_FORMAT = "%s%06d";
  
      public AdminResource(@Context GraphDatabaseService database) {
          super(database);
      }
  
      /**
       * Export the DB as a stream of JSON in
       * <a href="https://github.com/tinkerpop/blueprints/wiki/GraphSON-Reader-and-Writer-Library">GraphSON</a> format.
       * <p>
       * The mode used is EXTENDED.
       */
      @GET
      @Produces(MediaType.APPLICATION_JSON)
      @Path("export-graphson")
      public Response getGraphSON() throws Exception {
          return Response.ok((StreamingOutput) stream -> {
              try (final Tx tx = beginTx()) {
                  Accessor accessor = getRequesterUserProfile();
                  AclGraph<?> aclGraph = new AclGraph<Graph>(graph.getBaseGraph(), accessor);
                  GraphSONWriter.outputGraph(aclGraph, stream, GraphSONMode.EXTENDED);
                  tx.success();
              }
          }).build();
      }
  
      @GET
      @Produces(MediaType.APPLICATION_JSON)
      @Path("export-json")
      public Response exportNodes() throws Exception {
          return Response.ok((StreamingOutput) stream -> {
              try (final Tx tx = beginTx()) {
                  Accessor accessor = getRequesterUserProfile();
                 AclGraph<?> aclGraph = new AclGraph<Graph>(graph.getBaseGraph(), accessor);
                 JsonDataExporter.outputGraph(aclGraph, stream);
                 tx.success();
             }
         }).build();
     }
 
     /**
      * Create a new user with a default name and identifier.
      *
      * @param jsonData Additional key/value data for the created object
      * @param groups   IDs for groups to which the user should belong
      * @return A new user
      */
     @POST
     @Produces(MediaType.APPLICATION_JSON)
     @Consumes(MediaType.APPLICATION_JSON)
     @Path("create-default-user-profile")
     public Response createDefaultUserProfile(String jsonData,
             @QueryParam(GROUP_PARAM) List<String> groups) throws Exception {
         try (final Tx tx = beginTx()) {
             String ident = getNextDefaultUserId();
             Bundle bundle = Bundle.Builder.withClass(EntityClass.USER_PROFILE)
                     .addDataValue(Ontology.IDENTIFIER_KEY, ident)
                     .addDataValue(Ontology.NAME_KEY, ident)
                     .addData(parseUserData(jsonData))
                     .build();
 
             // NB: This assumes that admin's ID is the same as its identifier.
             Accessor admin = manager.getEntity(Group.ADMIN_GROUP_IDENTIFIER, Accessor.class);
             UserProfile user = api().withAccessor(admin).create(bundle, UserProfile.class);
 
             // add to the groups
             for (String groupId : groups) {
                 Group group = manager.getEntity(groupId, EntityClass.GROUP, Group.class);
                 group.addMember(user);
             }
 
             // Grant them owner permissions on their own account.
             api().aclManager().grantPermission(user, PermissionType.OWNER, user);
             Response response = creationResponse(user);
             tx.success();
             return response;
         }
     }
 
     // Helpers...
 
     private String getNextDefaultUserId() {
         try (CloseableIterable<Vertex> query = manager.getVertices(EntityClass.USER_PROFILE)) {
             long start = Iterables.size(query) + 1;
             while (manager.exists(String.format(DEFAULT_USER_ID_FORMAT,
                     DEFAULT_USER_ID_PREFIX, start))) start++;
             return String.format(DEFAULT_USER_ID_FORMAT, DEFAULT_USER_ID_PREFIX, start);
         }
     }
 
     private Map<String, Object> parseUserData(String json) throws IOException {
         if (json == null || json.trim().equals("")) {
             return Maps.newHashMap();
         } else {
             TypeReference<HashMap<String, Object>> typeRef = new TypeReference<
                     HashMap<String, Object>
                     >() {
             };
             return jsonMapper.readValue(json, typeRef);
         }
     }
 }